The present invention relates to filters, and more particularly to a filter assembly for use in filtering recirculating water in a spray booth.
Spray booths are used for a variety of purposes, for example, for spray painting articles. One of the problems encountered in spray booths is that of prevently escape of errant airborne particles. In paint spray booths, a solid sheet or curtain of water or a water spray intersects the path of air flowing through the booth and washes the particles out of the air. A holding tank is provided at the bottom of the booth to collect the wash water and a pump recirculates the water from the tank to the top of the booth.
It will be appreciated that the wash water used in these booths quickly becomes contaminated with the paint particles and it is necessary to continuously filter the water before redelivery by the pump to the top of the booth. Standard filtering assemblies include a screen over an intake pipe forming part of a conduit which connects the tank to the pump. The intake pipe is located near the bottom of the tank and because huge amounts of water are recirculated in this environment, the screen quickly becomes clogged. To clean the screen, it is necessary to shut down the booth and empty the water in the tank. This is very expensive not only because of lost time in operation of the spray booth but also because the water has chemicals added to it to prevent growth of algae and to consolidate the paint particles. Water containing these chemicals cannot be dumped into a sewer but must be sent off to an expensive disposal system.
The booth cannot be operated with a clogged filter or screen because the flow of water is reduced thereby reducing the effectiveness of the water wash system. Furthermore, should the filter or screen be completely clogged, the pump can overload and overheat. Therefore, it is desirable to provide a filter assembly for water wash spray booths which functions to satisfactorily filter the water and which allows for easy cleaning without requiring interruption of use of the spray booth and without requiring frequent disposal of the water.